From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 685B142D777; Wed, 2 Sep 2026 09:51:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788342660; cv=none; b=ObgHV46L+92AKawY9/Z2afJa1mbkkUuR42SKSJDR4e9dVjwB9p3r1HYier3pzxTih02yojh5C8ypdfrMv/nE83fky4n5u9r8ugnbFInizSE7rDpZiSe0q+qc7jIV7UlnP3wFT0WPMkjDQV+Aa5zVJmUT/QqgGLCiIr82n35IJF4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788342660; c=relaxed/simple; bh=Mo3+8RFfppINKIARqVbgEULhQ/6q8Q5E73vtDdVsNaQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JQF3e3/2tqhiRFMnhpkDj2z09XUWHYauncTD5WroGAQg0MBHbAttlw6cB6kTL3wAGMX4XjOM9xXRTbZIDUUTdkvplxVPflw+5YAPL9bnP0jvE5/+k2dvgVBhk8j2eY9aMUO7eRlEeBGvLOx75/hj0CxX2tLOsdkP2Gv8r8srdu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LjN8Jh71; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LjN8Jh71" Received: by smtp.kernel.org (Postfix) with ESMTPS id 2B516C2BD04; Wed, 2 Sep 2026 09:51:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1788342660; bh=Mo3+8RFfppINKIARqVbgEULhQ/6q8Q5E73vtDdVsNaQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=LjN8Jh71ESTtrz0II1QkWFMR6Ekn10yjUiU5wrtpB83llUdV/2TXESJKlYxXGJbFK BjL/hqJHbUqLQ+xQ7JKPNusWEkPdY3H3tSO0Tripls89K0PunwIWQZJCzgkJ01O9VE MF0jUHlUj8tq8RKt4PsFv4Ve+bB3kLb14TmcN12pef+qAjOXu9J5M6q/6aHQAvub+I wtL7Ub+pGmIsjG3jKL3/mxnsnakHKDJj4Ck/bM7+uPcLyFOxE0xC076uHuPhnmg5Ob +JvXfQKRavAYb/WERikZtdLsVUbzNO0i9U6pMdIidmI4xXF5ULRIzKAX1hAGCvxddi o+jRgTBAC38xg== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15FB7C61DD6; Wed, 2 Sep 2026 09:51:00 +0000 (UTC) From: Kairui Song via B4 Relay Date: Wed, 02 Sep 2026 17:50:58 +0800 Subject: [PATCH v5 5/6] mm/mglru: use explicit tier range in read_ctrl_pos() Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260902-mglru-flags-cleanup-v5-5-9db761d779ef@tencent.com> References: <20260902-mglru-flags-cleanup-v5-0-9db761d779ef@tencent.com> In-Reply-To: <20260902-mglru-flags-cleanup-v5-0-9db761d779ef@tencent.com> To: linux-mm@kvack.org Cc: Andrew Morton , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Shakeel Butt , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Chris Li , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Ridong Chen , Lian Wang , Yu Zhao , Zi Yan , Qi Zheng , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Kairui Song , Kairui Song X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1788342657; l=3649; i=kasong@tencent.com; s=kasong-sign-tencent; h=from:subject:message-id; bh=oVmtU7RtLEHATDqO9A5jftz8sm6P6wAktfihxMqJ5Tw=; b=dPPzLe7vps/4tFzAt1JpcbiW7bZLRHQCFNYaCQ4sCRNhFfKoV8rZMZJk4dpFzSA1X0k61uup7 ZtSlanhdkEYCfpC+U1UuJBSbBsreUiJ79Z2nOzSwDx7LLDmkPwdeE/2 X-Developer-Key: i=kasong@tencent.com; a=ed25519; pk=kCdoBuwrYph+KrkJnrr7Sm1pwwhGDdZKcKrqiK8Y1mI= X-Endpoint-Received: by B4 Relay for kasong@tencent.com/kasong-sign-tencent with auth_id=562 X-Original-From: Kairui Song Reply-To: kasong@tencent.com From: Kairui Song read_ctrl_pos() encodes the tier range in a single "tier" parameter via "tier % MAX_NR_TIERS" as the start and "min(tier, MAX_NR_TIERS-1)" as the end. This is hard to follow, maintain, or extend. Tier values 0..3 select a single tier, while tier == MAX_NR_TIERS selects the full range. Replace it with explicit (tier_min, tier_max) parameters using a closed [tier_min, tier_max] interval, and add LRU_TIER_MIN and LRU_TIER_MAX for the tier bounds. The call sites now become self-documenting: - get_tier_idx: (LRU_TIER_MIN, LRU_TIER_MIN) for the first tier, (tier, tier) for each subsequent tier - get_type_to_scan: (LRU_TIER_MIN, LRU_TIER_MAX) for the full range No functional change. Reviewed-by: Baolin Wang Reviewed-by: Baoquan He Reviewed-by: Barry Song Reviewed-by: Ridong Chen Signed-off-by: Kairui Song --- include/linux/mmzone.h | 2 ++ mm/vmscan.c | 18 ++++++++++-------- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c9ecf370cd9f..9b27cf53bdbc 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -492,6 +492,8 @@ enum lruvec_flags { * folio->flags, masked by LRU_REFS_MASK. */ #define MAX_NR_TIERS 4U +#define LRU_TIER_MIN 0U +#define LRU_TIER_MAX (MAX_NR_TIERS - 1) #ifndef __GENERATING_BOUNDS_H diff --git a/mm/vmscan.c b/mm/vmscan.c index 96fdfc14f615..714a3f273f49 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3198,8 +3198,8 @@ struct ctrl_pos { int gain; }; -static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain, - struct ctrl_pos *pos) +static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier_min, + int tier_max, int gain, struct ctrl_pos *pos) { int i; struct lru_gen_folio *lrugen = &lruvec->lrugen; @@ -3208,7 +3208,7 @@ static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain, pos->gain = gain; pos->refaulted = pos->total = 0; - for (i = tier % MAX_NR_TIERS; i <= min(tier, MAX_NR_TIERS - 1); i++) { + for (i = tier_min; i <= tier_max; i++) { pos->refaulted += lrugen->avg_refaulted[type][i] + atomic_long_read(&lrugen->refaulted[hist][type][i]); pos->total += lrugen->avg_total[type][i] + @@ -4809,9 +4809,9 @@ static int get_tier_idx(struct lruvec *lruvec, int type) * This value is chosen because any other tier would have at least twice * as many refaults as the first tier. */ - read_ctrl_pos(lruvec, type, 0, 2, &sp); - for (tier = 1; tier < MAX_NR_TIERS; tier++) { - read_ctrl_pos(lruvec, type, tier, 3, &pv); + read_ctrl_pos(lruvec, type, LRU_TIER_MIN, LRU_TIER_MIN, 2, &sp); + for (tier = LRU_TIER_MIN + 1; tier <= LRU_TIER_MAX; tier++) { + read_ctrl_pos(lruvec, type, tier, tier, 3, &pv); if (!positive_ctrl_err(&sp, &pv)) break; } @@ -4832,8 +4832,10 @@ static int get_type_to_scan(struct lruvec *lruvec, int swappiness) * Compare the sum of all tiers of anon with that of file to determine * which type to scan. */ - read_ctrl_pos(lruvec, LRU_GEN_ANON, MAX_NR_TIERS, swappiness, &sp); - read_ctrl_pos(lruvec, LRU_GEN_FILE, MAX_NR_TIERS, MAX_SWAPPINESS - swappiness, &pv); + read_ctrl_pos(lruvec, LRU_GEN_ANON, LRU_TIER_MIN, LRU_TIER_MAX, + swappiness, &sp); + read_ctrl_pos(lruvec, LRU_GEN_FILE, LRU_TIER_MIN, LRU_TIER_MAX, + MAX_SWAPPINESS - swappiness, &pv); return positive_ctrl_err(&sp, &pv); } -- 2.55.0